Braking device for internal-combustion engines



Sept. 14 1926.

. R n, m N 9 E :W W l m N, I G N E ,.N O I T A. Mm .OC HLL SM2. .IR Hmm CNU .IJ A d .Done vu EF C I V E D G N I K A Dn B Patented Sept. 14, 1926.

UNITED STATES VALENTINE A. CHISHOLM, 0F SEATTLE, WASHINGTON. i

BRAKING DEVICEIOB INTERNAL-COMBUSTION ENGINES.

Application led June 21,

This invention relates to internal combustion engines for motor vehicles and more especially to improved means for converting an engine from a vehicle motorinto a4 vehicle braking agency.

The object of the invention, generally, is the provision of inexpensively constructed, conveniently controlled and efiicient devices for accomplishing the purposes above men- -,tioned.

Other objects and advantages will be set forth in the following specification. y

The invention consists inthe novel construction, arrangement and combination of parts hereinafter described and claimed.

In the accompanying drawings,-

Figure 1 is an end elevation of an automobile engine with devices embodying my invention a plied thereto. Fig. 2 is a side elevation'oi) the same, part of the engine being broken away. Figs. 3 and 4 are vertical sectional views taken ylongitudinally of the engine of a portion of a fuel and air induction pipe for the intake manifold and illustrating' the controlling valve in its two operative positions. l

. In said drawing the reference numeral 5 represents in its entirety, a four-cycle internal combustion en ine of known or suit! able construction havmg the usual cam actuated intakepand exhaust valves,y not shown.

The stems, 6 and 7, of such intake and exhaust valves are actuated to open in proper sequence the respective valves in opposition to valve closing springs such as 8,

The cams for effecting the opening movements of the intake and exhaust valves are rigidly mounted upon shaftsl 9 and 10 respectively. The cam shaft 9 for the intake valves is driven from the 'engine crank shaft 11 through the medium of spur gears 12 and 13 having a gear ratio of one to two whereby the cam shaft is rotated at one-half the speed of the engine shaft.

The cam shaft 10 for the exhaust valveslis rotated at the same speed as the cam shaft 9 for the intake valves by means of an endless chain 1'4 passing about sprocket wheels 15.and 16 ri idly mounted upon the respective cam sha s. .A

17 represents the engine exhaust pipe and 18 is the induction pipe extending rom the carbureter 19 to the intake manifold 20.' y Y The parts hereinbefore described are or ma be constructed as hitherto. -4

ccordingto the present invention, how- 1924. Serial No.` 721,543.

ever, the fuel induction pipe 18 is formed as shown in Figs. 3 and 4, to provide aside opening 21 and a chamber 22 for a threeway valve 23 which is utilized to admit into the manifold 20 fuel from the carburcter and air from the external atmosphere when the valves are brought into approximately the position in which they are represented in Figs. 3 and 4, respectively.

24 represents an arm for the valve stem 231 which is connected by a pin 25 to a controll ng rod 26 whose other end is located within convenient reach of the automobile driver. The braking function ofthe invention is attained' upon occasion by employing means for regulating the chain 14 to rotatively advance the cam shaft 10 which governs the opening and closinfr movements of the engine exhaust valves. liith an Ottofour cycle engine the advance above referred to of the cam shaft is 1200, approximately.

As embodied, said means comprises a three-arm spider which is journaled to a stud 27 provided on the engine body, two of the spider arms 28 and 29 carry idler pulleys 30 and 31, respectively. These arms 28 and'29 are disposed 'at lan angle of 90o approximately from each other and are arranged to have both of the pulleys engage-- The third arm 32 of the spider is con-v nec'ted by a rod 3,3 with an arm 34 of a bellcrank lever which is fulcrumed to a relatively fixed stud 35. said lever being connected by a rod 37 with the pin 25 so as to be actuated by the automobile driver through the medium lof the controlling rod 26.

Normally, or when the engine is working as a motor, said spider occupies the osition in whichit is represented by full ines in Fig. 1 with the lower lead of the chain delected downwardly by means of the wheel 30, the other wheel 31 being idle. When the spider is brought into its dotted line position, Fig. 1, the wheel`30 becomes idle andA the other wheel 31 is swung into its dotted line 311 position resulting in the upper lead of the chainbeing deflected u wardly as indicated by dotted lines 141, gi 1. As this occurs, the slack, so to speak, o the lower lead is caused to ass .about the sprocket wheel 16 resulting in t e advancing 120, approximately, the cam shaft 10 which, in turn,

regulates. the exhaust valves to Cause the The other arm 36 of valves.

same to be open during the second down strokes of the pistons of the engine. The strokes above referred to correspond to the explosive strokes when the engine is utilized as a motor. It is to be understood, however, that the times and sequencel of the opening and closing of the inlet valves are in no way affected by the present invention, and the periods of action of. the exhaust valves are such that the air drawn into the cylinders during the respective suction strokes of the engine. is trapped within the cylinders and constitutes a retarding agent for reducing the speed of the engine and also the speed of the car when the transmission is in gear.

The occurrences of the open and closed'- periods of the exhaust valves are thus adv,justalole' relatively to the action ofthe camshaft 9 which controls the inlet valves.

The changes in the positions of; the spider are controlled .by the rod 26'Whicl1 likewise controls theaction of the three-way valve 23 so that the latter is held in position (Fig. 3) to afford a supply of fuel to the engine when it is operating as a motor, but when the spider is regulated to cause the engine to operate as a brake, the valve 23 is moved into a position (Fig. 4) to shut off the fuel supply and admit .air into the. cylinderssubject to regulation by ,the engine intake The operation of the invention will, it is thought, be understood from the foregoing description. It Will be understood that changes may be made from the precise forms of the devices herein shown and described,

within thscope of the accompanying claims, without departing" from the principles of the invention and without sacrificing its advanta es.

What I claim, 1s:-

1.' In aninternal combustion engine, the combination with the cam shafts for actuating the stems of the intake and exhaust valves for effecting the opening movements of the respective valves, means to drive the intake valve cam shaft, and transmission;v

Ameans for drivingl the exhaust cam shaft from the intake `cam shaft, of means for regulating said transmission means for advancing the rotation of the exhaust cam shaft relatively to the intake cam shaft;

2. In an internal combustion engine, the

' combination withthe engine crankshaft, a

Vcam shaft for the intake valves, and a train of air and gears operatively connecting the crank shaft with said cam shaft for driving the latter, of

a cam shaft for-the exhaust valves, sprocket i,

wheels provided on the respective cam shafts, an endless chain taking with said sprocket wheels for transmitting rotary motion from one cam shaft to the other, and Imeans for regulating said chain whereby the rotary motion of the cam shaft-of the exhaust valves is advanced and retarded selectively with respect to the other shaft.

In an internal combustion engine, the

combination with the cam shafts for the inlet and exhaust valves, toothed gears operated l.by the enginecrank shaft to drive the inlet necting said cam shaft with the cam shaft of the exhaust valves, and means operatively connected with said regulating valves for adjusting said transmission means for rotatively advancing 120 approximately the lastnamed cam shaft coincidently' with the setting of said regulating valve for the passage of air into and from the fuel intake. i A5. In an internal combustion engine, the combination with a fuel intake having an opening to the external atmosphere, and af three-wa -valve for admitting atmospheric 'el selectively into the, fuel intake, of a power driven inlet-valve cam-shaft, an exhaust-valve cam-shaft, chain devices for transmitting motion from the first to the second named cam-shaft, a spider for regulating said chain devices to impart an angu. lar movement to the second named shaft independently of the other shaft, and means.. for adjusting said spider, Vsaid`last'-namsd means being connected Ato said three-way. valve whereby the latter is actuated witlf' the adjusting of the spider. e

Signed at Seattle, Washington, th1s 9th. day of June1'924.

VALENTINE A. cHrsHoLM.

los 

